The field of the present invention is that of smoke-forming munitions.
Smoke-forming munitions having several pots of smoke-generating pyrotechnic composition disposed in the casing of an artillery shell are known. At a point in time determined by a timer rocket, the shell ejects the pots outside the casing on a trajectory. A pyrotechnic charge causes the pots to be both ejected and ignited. The pots strike the ground and generate a smoke screen opaque to radiation in the visible and/or infrared range, depending on the nature of the pyrotechnic composition contained in the pots.
Smoke-forming munitions having pots of pyrotechnic composition ejected out of a casing integral with a vehicle or a fixed structure are also known.
French Patent Appln. No. 8703415 (French Patent No. 2,612,287) describes such a munition, which allows both 1) a powder that quickly masks infrared radiation and 2) smoke-forming pots that generate an infrared-opaque screen, which is intended to remain durably in place, to be dispersed.
The above-described munitions have the disadvantage of not allowing good placement of the smoke-forming pots on the ground.
To create an efficient smoke screen, the pots forming the screen should not be too remote from each other (a relative distance of a few meters to a few tens of meters, depending on the volumes of the smoke pots) so that individual screens created by the pots overlap to form a larger screen.
Smoke pots ejected outside the body of a shell follow trajectories that are difficult to control and that depend on the altitude at which ejection is ordered. Hence, the pots arrive on the ground at relative distances that vary greatly from one shot to another, giving a random quality to the smoke screen obtained.
Leakage of ejection gases may also occur at the interface between two adjacent pots. Upon ejection, this leakage causes uncontrollable pot spacing.
Likewise, the munition of French Patent Appln. No. 8703415 keeps two smoke pots and a cartridge, containing masking powder, attached by a rod. A separation charge breaks the rod when the pots have been ejected outside the casing. After the rod breaks, however, the two smoke pots are no longer joined together and will strike the ground too far apart for the screen to be effective.
It is also very difficult to control the braking thrust produced by the separation charge in the smoke pots. This thrust causes relatively wide spacing between one munition and another, over the distances between the vehicle or structure to be screened and the smoke screen obtained.